Lunyu III. 12. (52)

Confucius's own sincerity in sacrificing.
1. He sacrificed to the dead, as if they were present. He sacrificed to the spirits, as if the spirits were present.
2. The Master said, "I consider my not being present at the sacrifice, as if I did not sacrifice."

Legge III.12.

'Sacrifice as if present' is taken to mean 'sacrifice to the gods as if gods were present.'
The Master, however, said, 'Unless I take part in a sacrifice, it is as if I did not sacrifice.